Van Gilder's Flashing Slip

I had a fellow ceramic artist ask me about the Van Gilder's flashing slip. Here's my understanding of it. The information presented is from my own experiences.

The Van Gilder's flashing slip is a thick slip that's available for use at the Irvine Fine Arts Center. It can be used thick for slip trailing or thinned down for painting application with a brush.

In theory, it is supposed to "flash" (ie have twinges/flashes of yellows, oranges) when you fire to Cone 10 reduction (highly reduced firing).  I've only seen in flash orange once on my pinch bowls and it was rather pretty.

I use it because it cracks predictably at Cone 10. It starts cracking after bisque fire to give you a nice texture. Most of the time, I use a wash of red iron oxide or manganese dioxide to impart color into the cracks. The red iron oxide will be anywhere from reddish brown to warm black. The manganese dioxide is blue black.  I sponge off the excess stain from the cracked surface leaving only the stains in the cracks. The piece is then fired to Cone 10 reduction (in a gas kiln).

When applied correctly, the results are very attractive. This piece has the flashing slip applied to the tentacled pods and the short stubby thorns.  I used manganese dioxide stain. You can see the cracking in those areas.

This is the kind of flashing that can happen in the correct environment. Notice the oranges.

Paperclay Sandwich

© 2009 Anthony Foo

The thing with commercially prepared paperclay is that you do not get the variety of clay bodies available as you do in traditional clays. My local distributor, Aardvark Clay Company carries the sculpture and throwing paperclay made by IMCO in Sacramento. Laguna Clay Company in Los Angeles recently started carrying their own version of Bmix + sand paperclay. Laguna Clay Company in Florida has a wider selection of paperclay (from low to high fire) but they do not ship to California.

As paperclay artists, unless you get into making your own paperclay, you are limited to what is commercially available.

In the past couple of years, I've started using the color and texture of the available clay as my color palette. That way, I don't have to deal with the issues of high fire glazes.

So .... how do I get these ordinary clay into my paperclay sculpture. My "Earthship" series employs a technique which I call "sandwiching." I don't know what is the proper name for it, but it's something I came up with because that is exactly what you do.

With the help of paperclay slip/slurry, I attach regular/ordinary clay onto my bone dry paperclay foundation. In this example, it is the "hull" of my "Earthship" series.

"Earthship 2"  and  "Earthship 3" has Grogzilla clay lumps stuck onto the ENTIRE outside of the piece. This Grogzilla clay has a high grog content with feldspar crystals in it. On high fire, the feldspar crystals "pop" and you get random pearl-like droplets (for lack of a better description). Sometimes they look like little white teeth. Maybe hence the name "Grogzilla." I really like this clay for its texture. The "Grogzilla" clay is available from Clay Planet, Santa Clara, CA.

The paperclay slip did not have any trouble holding on to the Grogzilla clay at all, although there was some surface cracking along the edges. I used more paperclay slip to cover up/seal the cracks as best I can. On both pieces, I used a Red Iron Oxide wash as a colorant. No glazes were used, with the exception of some flashing slip. Both pieces were fired to Cone 10 reduction and the sandwich technique performed and held up beautifully.

I have used this technique on either side of my pieces. In "Last Boat Out", I used Black Mountain sculpture clay on the inside of the hull. The outside rough texture was done with wet paperclay to dry technique.  I kept adding the wet paperclay to the dry foundation until I was satisfied with the thickness and shape/profile of the piece. Again, this was fired to Cone 10 reduction.

This "sandwich" technique will allow you to introduce readily available clay onto your paperclay structure.

Hopefully, you will find this discussion an inspiration to your own projects.